WebAssembly事始め（Chrome57記念）

$ WORKDIR=$(pwd)
$ git clone http://llvm.org/git/llvm.git
$ git clone http://llvm.org/git/clang.git llvm/tools/clang
$ git clone http://llvm.org/git/compiler-rt llvm/projects/compiler-rt
$ mkdir llvm_build
$ cd llvm_build/
$ cmake -G "Unix Makefiles" -DCMAKE_INSTALL_PREFIX=/usr/local -DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=WebAssembly "$WORKDIR/llvm"
$ make -j 8
$ sudo make install

$ git clone https://github.com/WebAssembly/binaryen.git
$ cd binaryen
$ cmake . && make
$ sudo make install

C source (.c)
-> LLVM-IR (.ll)
-> Assembly (.s)
-> WebAssembly text (.wast)
-> WebAssembly (.wasm)

int fib(n1, n2, i, max) {
 if (i == max) return n1;
 return fib(n2, n1 + n2, i + 1, max);
}

int fib_to(max) {
 return fib(0, 1, 0, max);
}

function fib(n1, n2, i, max) {
 if (i == max) return n1;
 return fib(n2, n1 + n2, i + 1, max);
}

function fib_to(max) {
 return fib(0, 1, 0, max);
}

$ cd src/
$ clang -S -emit-llvm -Oz --target=wasm32 fib.c
$ llc fib.ll -march=wasm32
$ s2wasm -s 100000 fib.s > fib.wast
$ wasm-as fib.wast > fib.wasm

fetch('./fib.wasm').then(response =>
 response.arrayBuffer()
).then(bytes =>
 WebAssembly.instantiate(bytes, {})
).then(result =>
 registerHandler('wasm', result.instance.exports.fib_to) // 別で定義
)

; ModuleID = 'fib.c'
source_filename = "fib.c"
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32"

; Function Attrs: minsize nounwind optsize readnone
define hidden i32 @fib(i32 %n1, i32 %n2, i32 %i, i32 %max) local_unnamed_addr #0 {
entry:
 br label %tailrecurse

tailrecurse: ; preds = %if.end, %entry
 %n1.tr = phi i32 [ %n1, %entry ], [ %n2.tr, %if.end ]
 %n2.tr = phi i32 [ %n2, %entry ], [ %add, %if.end ]
 %i.tr = phi i32 [ %i, %entry ], [ %add1, %if.end ]
 %cmp = icmp eq i32 %i.tr, %max
 br i1 %cmp, label %return, label %if.end

if.end: ; preds = %tailrecurse
 %add = add nsw i32 %n2.tr, %n1.tr
 %add1 = add nsw i32 %i.tr, 1
 br label %tailrecurse

return: ; preds = %tailrecurse
 ret i32 %n1.tr
}

; Function Attrs: minsize norecurse nounwind optsize readnone
define hidden i32 @fib_to(i32 %max) local_unnamed_addr #1 {
entry:
 br label %tailrecurse.i

tailrecurse.i: ; preds = %if.end.i, %entry
 %n1.tr.i = phi i32 [ 0, %entry ], [ %n2.tr.i, %if.end.i ]
 %n2.tr.i = phi i32 [ 1, %entry ], [ %add.i, %if.end.i ]
 %i.tr.i = phi i32 [ 0, %entry ], [ %add1.i, %if.end.i ]
 %cmp.i = icmp eq i32 %i.tr.i, %max
 br i1 %cmp.i, label %fib.exit, label %if.end.i

if.end.i: ; preds = %tailrecurse.i
 %add.i = add nsw i32 %n2.tr.i, %n1.tr.i
 %add1.i = add nuw nsw i32 %i.tr.i, 1
 br label %tailrecurse.i

fib.exit: ; preds = %tailrecurse.i
 ret i32 %n1.tr.i
}

attributes #0 = { minsize nounwind optsize readnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="generic" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { minsize norecurse nounwind optsize readnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="generic" "unsafe-fp-math"="false" "use-soft-float"="false" }

!llvm.ident = !{!0}

!0 = !{!"clang version 5.0.0 (http://llvm.org/git/clang.git e3a2454ea8263759d2ac667d3e086bb15269e10e) (http://llvm.org/git/llvm.git cd2a5b62d109d6864f2c566efab8e1dfb93f0550)"}

.text.file"fib.ll".hiddenfib.globlfib.typefib,@functionfib:# @fib.parami32,i32,i32,i32.resulti32# BB#0: # %entryi32.sub$3=,$3,$2.LBB0_1:# %tailrecurse# =>This Inner Loop Header: Depth=1blockloop# label1:i32.eqz$push1=,$3br_if1,$pop1# 1: down to label0# BB#2: # %if.end# in Loop: Header=BB0_1 Depth=1i32.const$push0=,-1i32.add$3=,$3,$pop0i32.add$2=,$1,$0copy_local$0=,$1copy_local$1=,$2br0# 0: up to label1.LBB0_3:# %returnend_loopend_block# label0:copy_local$push2=,$0# fallthrough-return: $pop2.endfunc.Lfunc_end0:.sizefib,.Lfunc_end0-fib.hiddenfib_to.globlfib_to.typefib_to,@functionfib_to:# @fib_to.parami32.resulti32.locali32,i32,i32# BB#0: # %entryi32.const$3=,1i32.const$2=,0.LBB1_1:# %tailrecurse.i# =>This Inner Loop Header: Depth=1blockloop# label3:i32.eqz$push1=,$0br_if1,$pop1# 1: down to label2# BB#2: # %if.end.i# in Loop: Header=BB1_1 Depth=1i32.const$push0=,-1i32.add$0=,$0,$pop0i32.add$1=,$3,$2copy_local$2=,$3copy_local$3=,$1br0# 0: up to label3.LBB1_3:# %fib.exitend_loopend_block# label2:copy_local$push2=,$2# fallthrough-return: $pop2.endfunc.Lfunc_end1:.sizefib_to,.Lfunc_end1-fib_to.ident"clang version 5.0.0 (http://llvm.org/git/clang.git e3a2454ea8263759d2ac667d3e086bb15269e10e) (http://llvm.org/git/llvm.git cd2a5b62d109d6864f2c566efab8e1dfb93f0550)"

(module
 (table 0 anyfunc)
 (memory $0 2)
 (data (i32.const 4) "\b0\86\01\00")
 (export "memory" (memory $0))
 (export "fib" (func $fib))
 (export "fib_to" (func $fib_to))
 (func $fib (param $0 i32) (param $1 i32) (param $2 i32) (param $3 i32) (result i32)
 (set_local $3
 (i32.sub
 (get_local $3)
 (get_local $2)
 )
 )
 (block $label$0
 (loop $label$1
 (br_if $label$0
 (i32.eqz
 (get_local $3)
 )
 )
 (set_local $3
 (i32.add
 (get_local $3)
 (i32.const -1)
 )
 )
 (set_local $2
 (i32.add
 (get_local $1)
 (get_local $0)
 )
 )
 (set_local $0
 (get_local $1)
 )
 (set_local $1
 (get_local $2)
 )
 (br $label$1)
 )
 )
 (get_local $0)
 )
 (func $fib_to (param $0 i32) (result i32)
 (local $1 i32)
 (local $2 i32)
 (local $3 i32)
 (set_local $3
 (i32.const 1)
 )
 (set_local $2
 (i32.const 0)
 )
 (block $label$0
 (loop $label$1
 (br_if $label$0
 (i32.eqz
 (get_local $0)
 )
 )
 (set_local $0
 (i32.add
 (get_local $0)
 (i32.const -1)
 )
 )
 (set_local $1
 (i32.add
 (get_local $3)
 (get_local $2)
 )
 )
 (set_local $2
 (get_local $3)
 )
 (set_local $3
 (get_local $1)
 )
 (br $label$1)
 )
 )
 (get_local $2)
 )
)